ary.map(item => item * 1000);
Good Part
ary.map(item => console.log(item) || item * 1000);
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ary.map(item => item * 1000);
Good Part
ary.map(item => console.log(item) || item * 1000);
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let / const
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let foo;
let bar;
if (new Date().getHours() < 12 ) {
foo = 'forenoon';
bar = 'am';
} else {
foo = 'afternoon';
bar = 'pm';
}
Bad Part
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let foo;
let bar;
if (new Date().getHours() < 12 ) {
foo = 'forenoon';
bar = 'am';
} else {
foo = 'afternoon';
bar = 'pm';
}
Bad Part
ίʔυ͕ංେԽ͢ΔʹͭΕͯletՄಡੑΛଛͳ͏
มએݴconstΛ͍ɺletۃྗ߇͑Δͷ͕·͍͠
ͦΕletΘͳͯ͘ग़དྷΔΑ
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Solution
ଈ࣌ؔΛ͏
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ଈ࣌ؔΛ͏
if elseΛଈ࣌ؔʹهड़͢Δ
ͦΕͧΕͷϒϩοΫͷ࠷ޙʹΛreturn͢ΕΓͲͪΒ͔ҰํͷΈͱ
ͳΔͷͰconst͕͑Δ
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const {foo, bar} = (() => {
if (new Date().getHours() < 12 ) {
return {
foo: 'forenoon',
bar: 'am'
};
} else {
return {
foo: 'afternoon',
bar: 'pm'
}
}
})();
Good Part
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array => hash
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use case
63-ΫΤϦύϥϝʔλΛ࿈ྻʹύʔε͢Δ
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// https://example.com/?utm_s=google&utm_m=ppc&utm_c=campaign1
const params = location.search.substring(1).split('&');
Bad Part
// [
// "utm_s=google",
// "utm_m=ppc",
// "utm_c=campaign1"
// ]
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// https://example.com/?utm_s=google&utm_m=ppc&utm_c=campaign1
const params = location.search.substring(1).split('&');
Bad Part
const result = {};
params.forEach(param => {
const pair = param.split('=');
result[pair[0]] = decodeURIComponent(pair[1]);
});
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Slide 30 text
// https://example.com/?utm_s=google&utm_m=ppc&utm_c=campaign1
const params = location.search.substring(1).split('&');
Bad Part
const result = {};
params.forEach(param => {
const pair = param.split('=');
result[pair[0]] = decodeURIComponent(pair[1]);
});
͍Ζ͍Ζͱ͗͢Δ
࠷ॳʹۭΦϒδΣΫτΛॳظͱͯ͠ఆٛ͠ɺϧʔϓॲཧͰΛ٧Ί͍͔ͯͳ
ͯ͘ͳΒͳ͍
5ZQF4DSJQUͩͱresultanyܕͰఆٛ͢Δ͜ͱʹͳͬͯ͠·͏ͷྑ͘ͳ͍